Expression of beta2 microglobulin (beta2m) in Escherichia coli resulted in formation of inclusion bodies. Attenuated total reflectance Fourier transform infrared analysis suggested a native-like secondary structure of beta2m in the inclusion bodies. Nondenaturing solubilization of the native-like beta2m from inclusion bodies was achieved Using L-arginine solution, which enables all efficient recovery of beta2m with little aggregation. Greater beta2m solubilization from inclusion bodies was obtained at higher temperatures. Low-temperature solubilization yielded beta2m with fluorescence properties identical to those of native beta2m, but its secondary structure was slightly normative. Solubilization at moderate temperature gave beta2m with an apparently native structure. We propose ail efficient nondenaturing solubilization method combining L-arginine and moderate temperature. (C) 2005 Elsevier Inc. All rights reserved.